Generator of electric relaxation oscillations



Dec. 21,.1937. E. HACKENBERG GENERATOR OF ELECTRIC RELAXATIONOSCILLATIONS Filed Jul s, 1936 eslsiarzce Fig. 2

Patented Dec. 21, 1937 UNlTED STATS GENERATOR OF ELEGTRIG RELAXATMDNOSCH'JLATIONS Application July 8,1936, Serial No.,89,649

In Germany July 11, 1935 3 Claims.

, The invention relates to devices for generating electric relaxationoscillations, that is, oscillations of the kind having a saw-toothshaped current curve. Devices of this nature are used in televisionsystems and are necessary also in connectionwith certain measuringequipments.

Such oscillation generators have the disadvantage that their saw-toothcurves are round at their lower angles while they should be acute orpointed there. 7,

In the. accompanying drawing:.

Fig. 1 shows a saw-tooth curve in its ideal and also in its realappearance. Fig. 2 is a wiring diagram of an embodiment of theinvention.

In Fig. 1 the ideal saw-toothcurve is designated i. The lower angles ofthis curve are acute while the curve really obtained is round at theseangles as indicated bythe dotted curve w. As a result the returnmovements of the beam of electrons are retarded in such a manner thatthere will be no image reproduction at a certain edge of the picture. Inthe case of measuring equipments this drawback acts to impair theoscillographic representation. r

Careful researches have shown these roundings tobe due'to the'fact thatthe condenser of the oscillation generator becomes recharged by the.

current source while still becoming discharged. The invention thereforeproposes to block up the charging circuit of the condenser during thedischarge thereof. Preferably this is performed with the aid of anelectron tube that serves to charge the condenser and is controlled bythe discharge current thereof.

The condenser is designated C in Fig. 2. The electron tube R, forinstance a Thyratrcn, is the tube of the relaxation circuit. .Thevoltage for charging the condenser C is supplied at terminals KI, K2.the relaxationoscillations is not of interest here. The customarycircuit arrangement may serve this purpose. In the feed line to therelaxation .circuit, that is, the line connected to Kl, a charging tubeL is included which by preference is a The mode of taking or derivinghigh vacuum multiple grid valve. A resistance JW and the internalresistance of the tube R constitute the ohmic resistance of therelaxation circuit, the frequency of this circuit being determined bythe product of the capacitive resistances by the ohmic ones. The controlgrid of the tube L is connected to the relaxation circuit at a pointbetween resistance W and tube R.

It is well known to employ charging tubes, such as L, in connection withrelaxation devices. It is not known; however, to employ the chargingtube for interrupting the flow of current during the discharge of thecondenser. When the condenser is discharging a current flows in thedirection of the arrow. As a result a drop of potential acrossresistance W occurs and thus a negative bias is produced that acts ontube L. The conditions are so chosen that the tube L will be blocked bythis negative potential as long as a current is flowing throughresistance W, that is to say, as long as condenser C is discharging. Assoon as such discharging is finished, the negative potentialceases toexist, the ourrent'immediately ceasing to flow,.and the condenser is newrecharged. Saw-tooth curves obtained with the aid of an arrangement ofthis special construction present the ideal appearance of the curve 2'in Fig. 1.

What is claimed is;

1. In a generator of electric relaxation oscillations, a condenser, acircuit for charging this condenser, a circuit for discharging it, andmeans to block up such charging circuit during the discharge of saidcondenser.

2. In a generator of electric relaxation oscillations, a condenser, acircuit for charging this condenser, a circuit for discharging it. anelectronic charging tube included in such charging circuit, and means tocontrol this tube by .the discharge current of said condenser.

3. An arrangement. according to claim 2, wherein the said charging tubeis a multiple grid valve.

- EDMUND HACKENBERG.

